Training for impact sports, self-defense, or combat applications such as law enforcement, and training for martial and other fighting arts, often requires that an individual perform strikes or impacts against a person or object. A number of conventional devices and methods are used to test and measure the power generated by martial or athletic impacts. These devices typically have significant shortcomings that prevent the collection of detailed, accurate data about the performance of the subject tested, and that prevent analysis of the data to the desired extent.
Applications of impact-measurement devices can be found in a number of conventional exercise and training devices. Usually, a purpose of these conventional devices is to monitor and/or direct an exercise workout or training session consisting of punches, kicks, or other simulated movements that involve impact. Measurements provided by these devices are often limited to counts of the number of impacts and simple approximations of impact power for each impact. Conventional devices do not normally provide immediate interactive feedback that would be useful for guiding the user in altering and/or refining his technique in response to the measurements as they are made. Consequently, conventional systems usually cannot provide sufficiently detailed data useful for analyzing a user's performance deficiencies in a manner that allows the user to alter his performance immediately or in real time in response to the data.
With respect to impacts delivered in martial arts and other sports, a person's ability to produce a displacement, a deformation, or a rupture in specific areas of a target is of concern. The objective of instruction and training in, for example, sports and martial arts is to enable an individual to reliably and efficiently perform strikes that produce the desired results, i.e., that produce ideal magnitudes of impact force in the proper directions. Traditionally, instructors have provided such instruction by observing the student's execution of a strike performed on an object and by observing and assessing the effects of the impact on the target. This traditional method of instruction usually precludes an ability to perform a visual observation of that portion of the strike at the brief instant in which the impact is actually occurring.
High-speed photography has been used in attempts to measure the velocities and directions of the fist, foot, shoulder, whole body, or other striking element prior to contact, as well as the displacement or deformation of the target during the impact. The magnitude and direction of the exerted force are then calculated using a best-guess estimate of the amount of target mass displaced and/or the extent of target deformation that occurs.
In these various conventional methods of testing impact forces and of assessing the results of impacts, a person (usually an instructor or physical therapist) is normally present with the person applying the impact in order to provide instruction, guidance, or feedback regarding the impacts. To date, there are no known modes by which a person can train for contact-related activity while receiving feedback (especially instantaneous feedback from both the target and a person having expertise in making optimal impacts with the target.
Efforts have conventionally been made to measure the effectiveness of an impact strike from data concerning only pre-impact momentum or from simple physical laws of motion and dynamics. However, these types of measurements tend to produce inaccurate results. A better way in which to measure forces produced during impacts is by using direct, real-time measurements of the effects of the impacts as the impacts are made on a target that is configured to provide measurements of the durations, directions, and magnitudes of the impacts. But, as noted above, known conventional devices lack this capability.
Many conventional strike-measurement devices are designed around the assumption that the force applied to a target is directly proportional to the momentum of the striking element (e.g., hand or foot) immediately preceding the impact with the target. However, the magnitude of the momentum (wherein momentum is equal to mass multiplied by velocity) generated prior to impact usually does not provide an accurate prediction of the magnitude of the actual force applied by the impact. This deficiency exists because conventional devices typically provide estimates of force independently of mass. Consequently, impact-force estimates provided by conventional devices can be insufficiently accurate for reliable or effective use in training.
Also, many conventional devices measure impact force one-dimensionally using force gauges. Unfortunately, one-dimensional force gauges are usually not effective tools for measuring the energy delivered from the various types of impacts described above because such gauges are designed to measure forces in only one direction. During an actual impact, the acceleration and impact vectors of an object striking a target are usually not one-dimensional linear; rather, these vectors almost always have components in multiple dimensions. Thus, a one-dimensional force gauge is usually unsatisfactory for measuring the angle of an impact and for providing data on other aspects of striking force such as multi-dimensional components of force vectors or even total impact force.
Other conventional devices measure impact forces applied to a target by mechanical forms of resistance such as mechanical springs, a suspended mass, an immovable object, or a variable resistance provided by another individual holding the target. Unfortunately, these devices typically cannot provide precise and consistent measurements of impact force. A suspended mass, an immovable object, or a variable resistance provides a resistance that increases proportionally with displacement of the target surface caused by the force of the impact. When training using these types of resistance, the athlete typically reduces the force of the strike quickly after making contact because sustaining or increasing the impact force after making contact with the target greatly increases the risk of injury to the athlete. As a result, the athlete is undesirably induced and conditioned to restrict or otherwise limit his strike in response to the physical limitations of the measurement device. Such conditioning typically leads the athlete away from sustaining a maximum application of impact force for the longest possible duration of impact.
Other conventional devices and methods are constructed of materials and employ methods that reduce the accuracy and consistency of the measurements. For example, certain devices measure impact forces applied against mechanical spring resistance or against hydraulic or pneumatic pressure generated by compression of a flexible, sealed member inside the target. Such types of devices do not exhibit adequate durability under the intense forces that can be generated by impacts to the target. In addition, impact resistance generated in this manner can be subject to substantial variation due to material fatigue and temperature variations. For example, springs usually exhibit changes in spring rate after repeated compression. Other “springy” components, such as fabrics, films, and foam rubber components, tend to stretch, weaken, and/or become more flexible upon receiving repeated impacts. These changes can substantially erode the consistency of measurements, even within a single testing session.
Another consideration in analyzing impact-strike performance is the time consumed in executing the strike. In conventional devices purportedly used for measuring the time consumed in executing impact strikes, the time data actually obtained usually pertain to time elapsed between giving the athlete a start signal and the instant the athlete makes contact with the target. Such a time measurement actually pertains to a combination of two separate events: the time required for the athlete's brain to recognize the start signal and to initiate muscle movement, and the elapsed time from commencing muscle movement initiating the strike to the onset of target displacement from the impact of the strike. Conventional devices are unsatisfactory in isolating and quantifying these two components separately.